// Copyright 2011 David Galles, University of San Francisco. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other materials
// provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// The views and conclusions contained in the software and documentation are those of the
// authors and should not be interpreted as representing official policies, either expressed
// or implied, of the University of San Francisco

function RedBlack(am, w, h) {
    this.init(am, w, h);

}

RedBlack.prototype = new Algorithm();
RedBlack.prototype.constructor = RedBlack;
RedBlack.superclass = Algorithm.prototype;

RedBlack.prototype.init = function (am, w, h) {
    var sc = RedBlack.superclass;
    var fn = sc.init;
    fn.call(this, am);
    this.addControls();
    this.nextIndex = 1;
    this.commands = [];
    this.startingX = w / 2;
    this.print_max = w - PRINT_HORIZONTAL_GAP;
    this.first_print_pos_y = h - 2 * PRINT_VERTICAL_GAP;


    this.cmd("CreateLabel", 0, "", EXPLANITORY_TEXT_X, EXPLANITORY_TEXT_Y, 0);
    this.animationManager.StartNewAnimation(this.commands);
    this.animationManager.skipForward();
    this.animationManager.clearHistory();

}

RedBlack.prototype.addControls = function () {
    this.insertField = addControlToAlgorithmBar("Text", "");
    this.insertField.onkeydown = this.returnSubmit(this.insertField, this.insertCallback.bind(this), 4);
    this.insertButton = addControlToAlgorithmBar("Button", "添加");
    this.insertButton.onclick = this.insertCallback.bind(this);
    this.deleteField = addControlToAlgorithmBar("Text", "");
    this.deleteField.onkeydown = this.returnSubmit(this.deleteField, this.deleteCallback.bind(this), 4);
    this.deleteButton = addControlToAlgorithmBar("Button", "删除");
    this.deleteButton.onclick = this.deleteCallback.bind(this);
    this.findField = addControlToAlgorithmBar("Text", "");
    this.findField.onkeydown = this.returnSubmit(this.findField, this.findCallback.bind(this), 4);
    this.findButton = addControlToAlgorithmBar("Button", "搜索");
    this.findButton.onclick = this.findCallback.bind(this);
    this.printButton = addControlToAlgorithmBar("Button", "打印");
    this.printButton.onclick = this.printCallback.bind(this);

    this.showNullLeaves = addCheckboxToAlgorithmBar("显示null叶子节点");
    this.showNullLeaves.onclick = this.showNullLeavesCallback.bind(this);
    this.showNullLeaves.checked = false;
    ;

}

RedBlack.prototype.reset = function () {
    this.nextIndex = 1;
    this.treeRoot = null;
}

var FIRST_PRINT_POS_X = 50;
var PRINT_VERTICAL_GAP = 20;
var PRINT_HORIZONTAL_GAP = 50;


var FOREGROUND_RED = "#ffffff";
var BACKGROUND_RED = "#ff0000";

var FOREGROUND_BLACK = "#ffffff"
var BACKGROUND_BLACK = "#000000";
var BACKGROUND_DOUBLE_BLACK = "#777777";


// var HIGHLIGHT_LABEL_COLOR = RED
// var HIGHLIGHT_LINK_COLOR = RED


var HIGHLIGHT_LABEL_COLOR = "#FF0000"
var HIGHLIGHT_LINK_COLOR = "#FF0000"

var BLUE = "#0000FF";

var LINK_COLOR = "#000000"
var BACKGROUND_COLOR = BACKGROUND_BLACK;
var HIGHLIGHT_COLOR = "#007700";
var FOREGROUND_COLOR = FOREGROUND_BLACK;
var PRINT_COLOR = FOREGROUND_COLOR

var widthDelta = 50;
var heightDelta = 50;
var startingY = 50;


var FIRST_PRINT_POS_X = 40;
var PRINT_VERTICAL_GAP = 20;
var PRINT_HORIZONTAL_GAP = 50;
var EXPLANITORY_TEXT_X = 10;
var EXPLANITORY_TEXT_Y = 10;

RedBlack.prototype.insertCallback = function (event) {
    var insertedValue = this.insertField.value;
    // Get text value
    insertedValue = this.normalizeNumber(insertedValue, 4);
    if (insertedValue != "") {
        // set text value
        this.insertField.value = "";
        this.implementAction(this.insertElement.bind(this), insertedValue);
    }
}

RedBlack.prototype.deleteCallback = function (event) {
    var deletedValue = this.deleteField.value;
    if (deletedValue != "") {
        deletedValue = this.normalizeNumber(deletedValue, 4);
        this.deleteField.value = "";
        this.implementAction(this.deleteElement.bind(this), deletedValue);
    }
}


RedBlack.prototype.findCallback = function (event) {
    var findValue = this.findField.value;
    if (findValue != "") {
        findValue = this.normalizeNumber(findValue, 4);
        this.findField.value = "";
        this.implementAction(this.findElement.bind(this), findValue);
    }
}

RedBlack.prototype.printCallback = function (event) {
    this.implementAction(this.printTree.bind(this), "");
}

RedBlack.prototype.showNullLeavesCallback = function (event) {
    if (this.showNullLeaves.checked) {
        this.animationManager.setAllLayers([0, 1]);
    } else {
        this.animationManager.setAllLayers([0]);
    }
}


RedBlack.prototype.printTree = function (unused) {
    this.commands = [];

    if (this.treeRoot != null) {
        this.highlightID = this.nextIndex++;
        var firstLabel = this.nextIndex;
        this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, this.treeRoot.x, this.treeRoot.y);
        this.xPosOfNextLabel = FIRST_PRINT_POS_X;
        this.yPosOfNextLabel = this.first_print_pos_y;
        this.printTreeRec(this.treeRoot);
        this.cmd("Delete", this.highlightID);
        this.cmd("Step");
        for (var i = firstLabel; i < this.nextIndex; i++)
            this.cmd("Delete", i);
        this.nextIndex = this.highlightID;  /// Reuse objects.  Not necessary.
    }
    return this.commands;
}

RedBlack.prototype.printTreeRec = function (tree) {
    this.cmd("Step");
    if (tree.left != null && !tree.left.phantomLeaf) {
        this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
        this.printTreeRec(tree.left);
        this.cmd("Move", this.highlightID, tree.x, tree.y);
        this.cmd("Step");
    }
    var nextLabelID = this.nextIndex++;
    this.cmd("CreateLabel", nextLabelID, tree.data, tree.x, tree.y);
    this.cmd("SetForegroundColor", nextLabelID, PRINT_COLOR);
    this.cmd("Move", nextLabelID, this.xPosOfNextLabel, this.yPosOfNextLabel);
    this.cmd("Step");

    this.xPosOfNextLabel += PRINT_HORIZONTAL_GAP;
    if (this.xPosOfNextLabel > this.print_max) {
        this.xPosOfNextLabel = FIRST_PRINT_POS_X;
        this.yPosOfNextLabel += PRINT_VERTICAL_GAP;

    }
    if (tree.right != null && !tree.right.phantomLeaf) {
        this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
        this.printTreeRec(tree.right);
        this.cmd("Move", this.highlightID, tree.x, tree.y);
        this.cmd("Step");
    }
    return;
}


RedBlack.prototype.findElement = function (findValue) {
    this.commands = [];

    this.highlightID = this.nextIndex++;

    this.doFind(this.treeRoot, findValue);


    return this.commands;
}


RedBlack.prototype.doFind = function (tree, value) {
    this.cmd("SetText", 0, "Searchiing for " + value);
    if (tree != null && !tree.phantomLeaf) {
        this.cmd("SetHighlight", tree.graphicID, 1);
        if (tree.data == value) {
            this.cmd("SetText", 0, "正在搜索 " + value + "：" + value + " = " + value + " (Element found!)");
            this.cmd("Step");
            this.cmd("SetText", 0, "Found:" + value);
            this.cmd("SetHighlight", tree.graphicID, 0);
        } else {
            if (tree.data > value) {
                this.cmd("SetText", 0, "正在搜索 " + value + "：" + value + " < " + tree.data + " （访问左子树）");
                this.cmd("Step");
                this.cmd("SetHighlight", tree.graphicID, 0);
                if (tree.left != null) {
                    this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
                    this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
                    this.cmd("Step");
                    this.cmd("Delete", this.highlightID);
                }
                this.doFind(tree.left, value);
            } else {
                this.cmd("SetText", 0, " 正在搜索 " + value + "：" + value + " > " + tree.data + " （访问右子树）");
                this.cmd("Step");
                this.cmd("SetHighlight", tree.graphicID, 0);
                if (tree.right != null) {
                    this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
                    this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
                    this.cmd("Step");
                    this.cmd("Delete", this.highlightID);
                }
                this.doFind(tree.right, value);
            }

        }

    } else {
        this.cmd("SetText", 0, " 正在搜索 " + value + "：" + "< 空树 > (找不到元素)");
        this.cmd("Step");
        this.cmd("SetText", 0, " 正在搜索 " + value + "：" + " (找不到元素)");
    }
}


RedBlack.prototype.findUncle = function (tree) {
    if (tree.parent == null) {
        return null;
    }
    var par = tree.parent;
    if (par.parent == null) {
        return null;
    }
    var grandPar = par.parent;

    if (grandPar.left == par) {
        return grandPar.right;
    } else {
        return grandPar.left;
    }
}


RedBlack.prototype.blackLevel = function (tree) {
    if (tree == null) {
        return 1;
    } else {
        return tree.blackLevel;
    }
}


RedBlack.prototype.attachLeftNullLeaf = function (node) {
    // Add phantom left leaf
    var treeNodeID = this.nextIndex++;
    this.cmd("CreateCircle", treeNodeID, "null", node.x, node.y);
    this.cmd("SetForegroundColor", treeNodeID, FOREGROUND_BLACK);
    this.cmd("SetBackgroundColor", treeNodeID, BACKGROUND_BLACK);
    node.left = new RedBlackNode("", treeNodeID, this.startingX, startingY);
    node.left.phantomLeaf = true;
    this.cmd("SetLayer", treeNodeID, 1);
    node.left.blackLevel = 1;
    this.cmd("Connect", node.graphicID, treeNodeID, LINK_COLOR);
}

RedBlack.prototype.attachRightNullLeaf = function (node) {
    // Add phantom right leaf
    treeNodeID = this.nextIndex++;
    this.cmd("CreateCircle", treeNodeID, "null", node.x, node.y);
    this.cmd("SetForegroundColor", treeNodeID, FOREGROUND_BLACK);
    this.cmd("SetBackgroundColor", treeNodeID, BACKGROUND_BLACK);
    node.right = new RedBlackNode("", treeNodeID, this.startingX, startingY);
    this.cmd("SetLayer", treeNodeID, 1);

    node.right.phantomLeaf = true;
    node.right.blackLevel = 1;
    this.cmd("Connect", node.graphicID, treeNodeID, LINK_COLOR);

}
RedBlack.prototype.attachNullLeaves = function (node) {
    this.attachLeftNullLeaf(node);
    this.attachRightNullLeaf(node);
}

RedBlack.prototype.insertElement = function (insertedValue) {
    this.commands = new Array();
    this.cmd("SetText", 0, " 正在添加 " + insertedValue);
    this.highlightID = this.nextIndex++;
    var treeNodeID;
    if (this.treeRoot == null) {
        treeNodeID = this.nextIndex++;
        this.cmd("CreateCircle", treeNodeID, insertedValue, this.startingX, startingY);
        this.cmd("SetForegroundColor", treeNodeID, FOREGROUND_BLACK);
        this.cmd("SetBackgroundColor", treeNodeID, BACKGROUND_BLACK);
        this.treeRoot = new RedBlackNode(insertedValue, treeNodeID, this.startingX, startingY);
        this.treeRoot.blackLevel = 1;

        this.attachNullLeaves(this.treeRoot);
        this.resizeTree();

    } else {
        treeNodeID = this.nextIndex++;

        this.cmd("CreateCircle", treeNodeID, insertedValue, 30, startingY);
        this.cmd("SetForegroundColor", treeNodeID, FOREGROUND_RED);
        this.cmd("SetBackgroundColor", treeNodeID, BACKGROUND_RED);
        this.cmd("Step");
        var insertElem = new RedBlackNode(insertedValue, treeNodeID, 100, 100)

        this.cmd("SetHighlight", insertElem.graphicID, 1);
        insertElem.height = 1;
        this.insert(insertElem, this.treeRoot);
        //				resizeTree();
    }
    this.cmd("SetText", 0, " ");
    return this.commands;
}


RedBlack.prototype.singleRotateRight = function (tree) {
    var B = tree;
    var t3 = B.right;
    var A = tree.left;
    var t1 = A.left;
    var t2 = A.right;

    this.cmd("SetText", 0, "右单旋");
    this.cmd("SetEdgeHighlight", B.graphicID, A.graphicID, 1);
    this.cmd("Step");

    // TODO:  Change link color

    if (t2 != null) {
        this.cmd("Disconnect", A.graphicID, t2.graphicID);
        this.cmd("Connect", B.graphicID, t2.graphicID, LINK_COLOR);
        t2.parent = B;
    }
    this.cmd("Disconnect", B.graphicID, A.graphicID);
    this.cmd("Connect", A.graphicID, B.graphicID, LINK_COLOR);

    A.parent = B.parent;
    if (this.treeRoot == B) {
        this.treeRoot = A;
    } else {
        this.cmd("Disconnect", B.parent.graphicID, B.graphicID, LINK_COLOR);
        this.cmd("Connect", B.parent.graphicID, A.graphicID, LINK_COLOR)
        if (B.isLeftChild()) {
            B.parent.left = A;
        } else {
            B.parent.right = A;
        }
    }
    A.right = B;
    B.parent = A;
    B.left = t2;
    this.resetHeight(B);
    this.resetHeight(A);
    this.resizeTree();
    return A;
}


RedBlack.prototype.singleRotateLeft = function (tree) {
    var A = tree;
    var B = tree.right;
    var t1 = A.left;
    var t2 = B.left;
    var t3 = B.right;

    this.cmd("SetText", 0, "左单旋");
    this.cmd("SetEdgeHighlight", A.graphicID, B.graphicID, 1);
    this.cmd("Step");

    if (t2 != null) {
        this.cmd("Disconnect", B.graphicID, t2.graphicID);
        this.cmd("Connect", A.graphicID, t2.graphicID, LINK_COLOR);
        t2.parent = A;
    }
    this.cmd("Disconnect", A.graphicID, B.graphicID);
    this.cmd("Connect", B.graphicID, A.graphicID, LINK_COLOR);
    B.parent = A.parent;
    if (this.treeRoot == A) {
        this.treeRoot = B;
    } else {
        this.cmd("Disconnect", A.parent.graphicID, A.graphicID, LINK_COLOR);
        this.cmd("Connect", A.parent.graphicID, B.graphicID, LINK_COLOR)

        if (A.isLeftChild()) {
            A.parent.left = B;
        } else {
            A.parent.right = B;
        }
    }
    B.left = A;
    A.parent = B;
    A.right = t2;
    this.resetHeight(A);
    this.resetHeight(B);

    this.resizeTree();
    return B;
}


RedBlack.prototype.getHeight = function (tree) {
    if (tree == null) {
        return 0;
    }
    return tree.height;
}

RedBlack.prototype.resetHeight = function (tree) {
    if (tree != null) {
        var newHeight = Math.max(this.getHeight(tree.left), this.getHeight(tree.right)) + 1;
        if (tree.height != newHeight) {
            tree.height = Math.max(this.getHeight(tree.left), this.getHeight(tree.right)) + 1
        }
    }
}

RedBlack.prototype.insert = function (elem, tree) {
    this.cmd("SetHighlight", tree.graphicID, 1);
    this.cmd("SetHighlight", elem.graphicID, 1);

    if (elem.data < tree.data) {
        this.cmd("SetText", 0, elem.data + " < " + tree.data + "， 访问左子树");
    } else {
        this.cmd("SetText", 0, elem.data + " >= " + tree.data + "， 访问右子树");
    }
    this.cmd("Step");
    this.cmd("SetHighlight", tree.graphicID, 0);
    this.cmd("SetHighlight", elem.graphicID, 0);

    if (elem.data < tree.data) {
        if (tree.left == null || tree.left.phantomLeaf) {
            this.cmd("SetText", 0, "Found null tree (or phantom leaf), inserting element");
            if (tree.left != null) {
                this.cmd("Delete", tree.left.graphicID);
            }
            this.cmd("SetHighlight", elem.graphicID, 0);
            tree.left = elem;
            elem.parent = tree;
            this.cmd("Connect", tree.graphicID, elem.graphicID, LINK_COLOR);

            this.attachNullLeaves(elem);
            this.resizeTree();


            this.resizeTree();

            this.fixDoubleRed(elem);

        } else {
            this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
            this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
            this.cmd("Step");
            this.cmd("Delete", this.highlightID);
            this.insert(elem, tree.left);

        }
    } else {
        if (tree.right == null || tree.right.phantomLeaf) {
            this.cmd("SetText", 0, "Found null tree (or phantom leaf), inserting element");
            if (tree.right != null) {
                this.cmd("Delete", tree.right.graphicID);
            }

            this.cmd("SetHighlight", elem.graphicID, 0);
            tree.right = elem;
            elem.parent = tree;
            this.cmd("Connect", tree.graphicID, elem.graphicID, LINK_COLOR);
            elem.x = tree.x + widthDelta / 2;
            elem.y = tree.y + heightDelta
            this.cmd("Move", elem.graphicID, elem.x, elem.y);


            this.attachNullLeaves(elem);
            this.resizeTree();


            this.resizeTree();
            this.fixDoubleRed(elem);
        } else {
            this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
            this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
            this.cmd("Step");
            this.cmd("Delete", this.highlightID);
            this.insert(elem, tree.right);
        }
    }


}


RedBlack.prototype.fixDoubleRed = function (tree) {
    if (tree.parent != null) {
        if (tree.parent.blackLevel > 0) {
            return;
        }
        if (tree.parent.parent == null) {
            this.cmd("SetText", 0, "Tree root is red, color it black.");
            this.cmd("Step");
            tree.parent.blackLevel = 1;
            this.cmd("SetForegroundColor", tree.parent.graphicID, FOREGROUND_BLACK);
            this.cmd("SetBackgroundColor", tree.parent.graphicID, BACKGROUND_BLACK);
            return;
        }
        var uncle = this.findUncle(tree);
        if (this.blackLevel(uncle) == 0) {
            this.cmd("SetText", 0, "Node and parent are both red.  Uncle of node is red -- push blackness down from grandparent");
            this.cmd("Step");

            this.cmd("SetForegroundColor", uncle.graphicID, FOREGROUND_BLACK);
            this.cmd("SetBackgroundColor", uncle.graphicID, BACKGROUND_BLACK);
            uncle.blackLevel = 1;

            tree.parent.blackLevel = 1;
            this.cmd("SetForegroundColor", tree.parent.graphicID, FOREGROUND_BLACK);
            this.cmd("SetBackgroundColor", tree.parent.graphicID, BACKGROUND_BLACK);

            tree.parent.parent.blackLevel = 0;
            this.cmd("SetForegroundColor", tree.parent.parent.graphicID, FOREGROUND_RED);
            this.cmd("SetBackgroundColor", tree.parent.parent.graphicID, BACKGROUND_RED);
            this.cmd("Step");
            this.fixDoubleRed(tree.parent.parent);
        } else {
            if (tree.isLeftChild() && !tree.parent.isLeftChild()) {
                this.cmd("SetText", 0, "Node and parent are both red.  Node is left child, parent is right child -- rotate");
                this.cmd("Step");

                this.singleRotateRight(tree.parent);
                tree = tree.right;

            } else if (!tree.isLeftChild() && tree.parent.isLeftChild()) {
                this.cmd("SetText", 0, "Node and parent are both red.  Node is right child, parent is left child -- rotate");
                this.cmd("Step");

                this.singleRotateLeft(tree.parent);
                tree = tree.left;
            }

            if (tree.isLeftChild()) {
                this.cmd("SetText", 0, "Node and parent are both red.  Node is left child, parent is left child\nCan fix extra redness with a single rotation");
                this.cmd("Step");

                this.singleRotateRight(tree.parent.parent);
                tree.parent.blackLevel = 1;
                this.cmd("SetForegroundColor", tree.parent.graphicID, FOREGROUND_BLACK);
                this.cmd("SetBackgroundColor", tree.parent.graphicID, BACKGROUND_BLACK);

                tree.parent.right.blackLevel = 0;
                this.cmd("SetForegroundColor", tree.parent.right.graphicID, FOREGROUND_RED);
                this.cmd("SetBackgroundColor", tree.parent.right.graphicID, BACKGROUND_RED);


            } else {
                this.cmd("SetText", 0, "Node and parent are both red.  Node is right child, parent is right child\nCan fix extra redness with a single rotation");
                this.cmd("Step");

                this.singleRotateLeft(tree.parent.parent);
                tree.parent.blackLevel = 1;
                this.cmd("SetForegroundColor", tree.parent.graphicID, FOREGROUND_BLACK);
                this.cmd("SetBackgroundColor", tree.parent.graphicID, BACKGROUND_BLACK);

                tree.parent.left.blackLevel = 0;
                this.cmd("SetForegroundColor", tree.parent.left.graphicID, FOREGROUND_RED);
                this.cmd("SetBackgroundColor", tree.parent.left.graphicID, BACKGROUND_RED);

            }
        }

    } else {
        if (tree.blackLevel == 0) {
            this.cmd("SetText", 0, "Root of the tree is red.  Color it black");
            this.cmd("Step");

            tree.blackLevel = 1;
            this.cmd("SetForegroundColor", tree.graphicID, FOREGROUND_BLACK);
            this.cmd("SetBackgroundColor", tree.graphicID, BACKGROUND_BLACK);
        }
    }

}

RedBlack.prototype.deleteElement = function (deletedValue) {
    this.commands = new Array();
    this.cmd("SetText", 0, "正在刪除 " + deletedValue);
    this.cmd("Step");
    this.cmd("SetText", 0, " ");
    this.highlightID = this.nextIndex++;
    this.treeDelete(this.treeRoot, deletedValue);
    this.cmd("SetText", 0, " ");
    // Do delete
    return this.commands;
}


RedBlack.prototype.fixLeftNull = function (tree) {
    var treeNodeID = this.nextIndex++;
    var nullLeaf;
    this.cmd("SetText", 0, "Coloring 'Null Leaf' double black");

    this.cmd("CreateCircle", treeNodeID, "null", tree.x, tree.y);
    this.cmd("SetForegroundColor", treeNodeID, FOREGROUND_BLACK);
    this.cmd("SetBackgroundColor", treeNodeID, BACKGROUND_DOUBLE_BLACK);
    nullLeaf = new RedBlackNode("null", treeNodeID, tree.x, tree.x);
    nullLeaf.blackLevel = 2;
    nullLeaf.parent = tree;
    nullLeaf.phantomLeaf = true;
    tree.left = nullLeaf;
    this.cmd("Connect", tree.graphicID, nullLeaf.graphicID, LINK_COLOR);

    this.resizeTree();
    this.fixExtraBlackChild(tree, true);
    this.cmd("SetLayer", nullLeaf.graphicID, 1);
    nullLeaf.blackLevel = 1;
    this.fixNodeColor(nullLeaf);
}


RedBlack.prototype.fixRightNull = function (tree) {
    var treeNodeID = this.nextIndex++;
    var nullLeaf;
    this.cmd("SetText", 0, "Coloring 'Null Leaf' double black");

    this.cmd("CreateCircle", treeNodeID, "null", tree.x, tree.y);
    this.cmd("SetForegroundColor", treeNodeID, FOREGROUND_BLACK);
    this.cmd("SetBackgroundColor", treeNodeID, BACKGROUND_DOUBLE_BLACK);
    nullLeaf = new RedBlackNode("null", treeNodeID, tree.x, tree.x);
    nullLeaf.parent = tree;
    nullLeaf.phantomLeaf = true;
    nullLeaf.blackLevel = 2;
    tree.right = nullLeaf;
    this.cmd("Connect", tree.graphicID, nullLeaf.graphicID, LINK_COLOR);

    this.resizeTree();

    this.fixExtraBlackChild(tree, false);

    this.cmd("SetLayer", nullLeaf.graphicID, 1);
    nullLeaf.blackLevel = 1;
    this.fixNodeColor(nullLeaf);

}


RedBlack.prototype.fixExtraBlackChild = function (parNode, isLeftChild) {
    var sibling;
    var doubleBlackNode;
    if (isLeftChild) {
        sibling = parNode.right;
        doubleBlackNode = parNode.left;
    } else {
        sibling = parNode.left;
        doubleBlackNode = parNode.right;
    }
    if (this.blackLevel(sibling) > 0 && this.blackLevel(sibling.left) > 0 && this.blackLevel(sibling.right) > 0) {
        this.cmd("SetText", 0, "Double black node has black sibling and 2 black nephews.  Push up black level");
        this.cmd("Step");
        sibling.blackLevel = 0;
        this.fixNodeColor(sibling);
        if (doubleBlackNode != null) {
            doubleBlackNode.blackLevel = 1;
            this.fixNodeColor(doubleBlackNode);

        }
        if (parNode.blackLevel == 0) {
            parNode.blackLevel = 1;
            this.fixNodeColor(parNode);
        } else {
            parNode.blackLevel = 2;
            this.fixNodeColor(parNode);
            this.cmd("SetText", 0, "Pushing up black level created another double black node.  Repeating ...");
            this.cmd("Step");
            this.fixExtraBlack(parNode);
        }
    } else if (this.blackLevel(sibling) == 0) {
        this.cmd("SetText", 0, "Double black node has red sibling.  Rotate tree to make sibling black ...");
        this.cmd("Step");
        if (isLeftChild) {
            var newPar = this.singleRotateLeft(parNode);
            newPar.blackLevel = 1;
            this.fixNodeColor(newPar);
            newPar.left.blackLevel = 0;
            this.fixNodeColor(newPar.left);
            this.cmd("Step"); // TODO:  REMOVE
            this.fixExtraBlack(newPar.left.left);

        } else {
            newPar = this.singleRotateRight(parNode);
            newPar.blackLevel = 1;
            this.fixNodeColor(newPar);
            newPar.right.blackLevel = 0;
            this.fixNodeColor(newPar.right);
            this.cmd("Step"); // TODO:  REMOVE

            this.fixExtraBlack(newPar.right.right);
        }
    } else if (isLeftChild && this.blackLevel(sibling.right) > 0) {
        this.cmd("SetText", 0, "Double black node has black sibling, but double black node is a left child, \nand the right nephew is black.  Rotate tree to make opposite nephew red ...");
        this.cmd("Step");

        var newSib = this.singleRotateRight(sibling);
        newSib.blackLevel = 1;
        this.fixNodeColor(newSib);
        newSib.right.blackLevel = 0;
        this.fixNodeColor(newSib.right);
        this.cmd("Step");
        this.fixExtraBlackChild(parNode, isLeftChild);
    } else if (!isLeftChild && this.blackLevel(sibling.left) > 0) {
        this.cmd("SetText", 0, "Double black node has black sibling, but double black node is a right child, \nand the left nephew is black.  Rotate tree to make opposite nephew red ...");
        this.cmd("Step");
        newSib = this.singleRotateLeft(sibling);
        newSib.blackLevel = 1;
        this.fixNodeColor(newSib);
        newSib.left.blackLevel = 0;
        this.fixNodeColor(newSib.left);
        this.cmd("Step");
        this.fixExtraBlackChild(parNode, isLeftChild);
    } else if (isLeftChild) {
        this.cmd("SetText", 0, "Double black node has black sibling, is a left child, and its right nephew is red.\nOne rotation can fix double-blackness.");
        this.cmd("Step");

        var oldParBlackLevel = parNode.blackLevel;
        newPar = this.singleRotateLeft(parNode);
        if (oldParBlackLevel == 0) {
            newPar.blackLevel = 0;
            this.fixNodeColor(newPar);
            newPar.left.blackLevel = 1;
            this.fixNodeColor(newPar.left);
        }
        newPar.right.blackLevel = 1;
        this.fixNodeColor(newPar.right);
        if (newPar.left.left != null) {
            newPar.left.left.blackLevel = 1;
            this.fixNodeColor(newPar.left.left);
        }
    } else {
        this.cmd("SetText", 0, "Double black node has black sibling, is a right child, and its left nephew is red.\nOne rotation can fix double-blackness.");
        this.cmd("Step");

        oldParBlackLevel = parNode.blackLevel;
        newPar = this.singleRotateRight(parNode);
        if (oldParBlackLevel == 0) {
            newPar.blackLevel = 0;
            this.fixNodeColor(newPar);
            newPar.right.blackLevel = 1;
            this.fixNodeColor(newPar.right);
        }
        newPar.left.blackLevel = 1;
        this.fixNodeColor(newPar.left);
        if (newPar.right.right != null) {
            newPar.right.right.blackLevel = 1;
            this.fixNodeColor(newPar.right.right);
        }
    }
}


RedBlack.prototype.fixExtraBlack = function (tree) {
    if (tree.blackLevel > 1) {
        if (tree.parent == null) {
            this.cmd("SetText", 0, "Double black node is root.  Make it single black.");
            this.cmd("Step");

            tree.blackLevel = 1;
            this.cmd("SetBackgroundColor", tree.graphicID, BACKGROUND_BLACK);
        } else if (tree.parent.left == tree) {
            this.fixExtraBlackChild(tree.parent, true);
        } else {
            this.fixExtraBlackChild(tree.parent, false);
        }

    } else {
        // No extra blackness
    }
}


RedBlack.prototype.treeDelete = function (tree, valueToDelete) {
    var leftchild = false;
    if (tree != null && !tree.phantomLeaf) {
        if (tree.parent != null) {
            leftchild = tree.parent.left == tree;
        }
        this.cmd("SetHighlight", tree.graphicID, 1);
        if (valueToDelete < tree.data) {
            this.cmd("SetText", 0, valueToDelete + " < " + tree.data + "， 访问左子树");
        } else if (valueToDelete > tree.data) {
            this.cmd("SetText", 0, valueToDelete + " > " + tree.data + "， 访问右子树");
        } else {
            this.cmd("SetText", 0, valueToDelete + " == " + tree.data + ".  Found node to delete");
        }
        this.cmd("Step");
        this.cmd("SetHighlight", tree.graphicID, 0);

        if (valueToDelete == tree.data) {
            var needFix = tree.blackLevel > 0;
            if (((tree.left == null) || tree.left.phantomLeaf) && ((tree.right == null) || tree.right.phantomLeaf)) {
                this.cmd("SetText", 0, "需要删除的是叶子节点，直接删除！");
                this.cmd("Delete", tree.graphicID);

                if (tree.left != null) {
                    this.cmd("Delete", tree.left.graphicID);
                }
                if (tree.right != null) {
                    this.cmd("Delete", tree.right.graphicID);
                }


                if (leftchild && tree.parent != null) {
                    tree.parent.left = null;
                    this.resizeTree();

                    if (needFix) {
                        this.fixLeftNull(tree.parent);
                    } else {

                        this.attachLeftNullLeaf(tree.parent);
                        this.resizeTree();
                    }
                } else if (tree.parent != null) {
                    tree.parent.right = null;
                    this.resizeTree();
                    if (needFix) {
                        this.fixRightNull(tree.parent);
                    } else {
                        this.attachRightNullLeaf(tree.parent);
                        this.resizeTree();
                    }
                } else {
                    this.treeRoot = null;
                }

            } else if (tree.left == null || tree.left.phantomLeaf) {
                this.cmd("SetText", 0, "需要删除的节点没有左子树.  \nSet parent of deleted node to right child of deleted node.");
                if (tree.left != null) {
                    this.cmd("Delete", tree.left.graphicID);
                    tree.left = null;
                }

                if (tree.parent != null) {
                    this.cmd("Disconnect", tree.parent.graphicID, tree.graphicID);
                    this.cmd("Connect", tree.parent.graphicID, tree.right.graphicID, LINK_COLOR);
                    this.cmd("Step");
                    this.cmd("Delete", tree.graphicID);
                    if (leftchild) {
                        tree.parent.left = tree.right;
                        if (needFix) {
                            this.cmd("SetText", 0, "Back node removed.  Increasing child's blackness level");
                            tree.parent.left.blackLevel++;
                            this.fixNodeColor(tree.parent.left);
                            this.fixExtraBlack(tree.parent.left);
                        }
                    } else {
                        tree.parent.right = tree.right;
                        if (needFix) {
                            tree.parent.right.blackLevel++;
                            this.cmd("SetText", 0, "Back node removed.  Increasing child's blackness level");
                            this.fixNodeColor(tree.parent.right);
                            this.fixExtraBlack(tree.parent.right);
                        }

                    }
                    tree.right.parent = tree.parent;
                } else {
                    this.cmd("Delete", tree.graphicID);
                    this.treeRoot = tree.right;
                    this.treeRoot.parent = null;
                    if (this.treeRoot.blackLevel == 0) {
                        this.treeRoot.blackLevel = 1;
                        this.cmd("SetForegroundColor", this.treeRoot.graphicID, FOREGROUND_BLACK);
                        this.cmd("SetBackgroundColor", this.treeRoot.graphicID, BACKGROUND_BLACK);
                    }
                }
                this.resizeTree();
            } else if (tree.right == null || tree.right.phantomLeaf) {
                this.cmd("SetText", 0, "需要删除的节点没有右子树.  \nSet parent of deleted node to left child of deleted node.");
                if (tree.right != null) {
                    this.cmd("Delete", tree.right.graphicID);
                    tree.right = null;
                }
                if (tree.parent != null) {
                    this.cmd("Disconnect", tree.parent.graphicID, tree.graphicID);
                    this.cmd("Connect", tree.parent.graphicID, tree.left.graphicID, LINK_COLOR);
                    this.cmd("Step");
                    this.cmd("Delete", tree.graphicID);
                    if (leftchild) {
                        tree.parent.left = tree.left;
                        if (needFix) {
                            tree.parent.left.blackLevel++;
                            this.fixNodeColor(tree.parent.left);
                            this.fixExtraBlack(tree.parent.left);
                            this.resizeTree();
                        } else {
                            this.cmd("SetText", 0, "删除的是红色节点.  不需要旋转.");
                            this.resizeTree();

                        }
                    } else {
                        tree.parent.right = tree.left;
                        if (needFix) {
                            tree.parent.right.blackLevel++;
                            this.fixNodeColor(tree.parent.right);
                            this.fixExtraBlack(tree.parent.left);
                            this.resizeTree();
                        } else {
                            this.cmd("SetText", 0, "删除的是红色节点.  不需要旋转.");
                            this.resizeTree();
                        }
                    }
                    tree.left.parent = tree.parent;
                } else {
                    this.cmd("Delete", tree.graphicID);
                    this.treeRoot = tree.left;
                    this.treeRoot.parent = null;
                    if (this.treeRoot.blackLevel == 0) {
                        this.treeRoot.blackLevel = 1;
                        this.fixNodeColor(this.treeRoot);
                    }
                }
            } else // tree.left != null && tree.right != null
            {
                this.cmd("SetText", 0, "需要删除的节点有2棵子树.  \n找到左子树中最大的节点.");

                this.highlightID = this.nextIndex;
                this.nextIndex += 1;
                this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
                var tmp = tree;
                tmp = tree.left;
                this.cmd("Move", this.highlightID, tmp.x, tmp.y);
                this.cmd("Step");
                while (tmp.right != null && !tmp.right.phantomLeaf) {
                    tmp = tmp.right;
                    this.cmd("Move", this.highlightID, tmp.x, tmp.y);
                    this.cmd("Step");
                }
                if (tmp.right != null) {
                    this.cmd("Delete", tmp.right.graphicID);
                    tmp.right = null;
                }
                this.cmd("SetText", tree.graphicID, " ");
                var labelID = this.nextIndex;
                this.nextIndex += 1;
                this.cmd("CreateLabel", labelID, tmp.data, tmp.x, tmp.y);
                this.cmd("SetForegroundColor", labelID, BLUE);
                tree.data = tmp.data;
                this.cmd("Move", labelID, tree.x, tree.y);
                this.cmd("SetText", 0, "Copy largest value of left subtree into node to delete.");

                this.cmd("Step");
                this.cmd("SetHighlight", tree.graphicID, 0);
                this.cmd("Delete", labelID);
                this.cmd("SetText", tree.graphicID, tree.data);
                this.cmd("Delete", this.highlightID);
                this.cmd("SetText", 0, "Remove node whose value we copied.");

                needFix = tmp.blackLevel > 0;


                if (tmp.left == null) {
                    this.cmd("Delete", tmp.graphicID);
                    if (tmp.parent != tree) {
                        tmp.parent.right = null;
                        this.resizeTree();
                        if (needFix) {
                            this.fixRightNull(tmp.parent);
                        } else {
                            this.cmd("SetText", 0, "删除的是红色节点.  不需要旋转.");
                            this.cmd("Step");
                        }
                    } else {
                        tree.left = null;
                        this.resizeTree();
                        if (needFix) {
                            this.fixLeftNull(tmp.parent);
                        } else {
                            this.cmd("SetText", 0, "删除的是红色节点.  不需要旋转.");
                            this.cmd("Step");
                        }
                    }
                } else {
                    this.cmd("Disconnect", tmp.parent.graphicID, tmp.graphicID);
                    this.cmd("Connect", tmp.parent.graphicID, tmp.left.graphicID, LINK_COLOR);
                    this.cmd("Step");
                    this.cmd("Delete", tmp.graphicID);

                    if (tmp.parent != tree) {
                        tmp.parent.right = tmp.left;
                        tmp.left.parent = tmp.parent;
                        this.resizeTree();

                        if (needFix) {
                            this.cmd("SetText", 0, "Coloring child of deleted node black");
                            this.cmd("Step");
                            tmp.left.blackLevel++;
                            if (tmp.left.phantomLeaf) {
                                this.cmd("SetLayer", tmp.left.graphicID, 0);
                            }
                            this.fixNodeColor(tmp.left);
                            this.fixExtraBlack(tmp.left);
                            if (tmp.left.phantomLeaf) {
                                this.cmd("SetLayer", tmp.left.graphicID, 1);
                            }

                        } else {
                            this.cmd("SetText", 0, "删除的是红色节点.  不需要旋转.");
                            this.cmd("Step");
                        }
                    } else {
                        tree.left = tmp.left;
                        tmp.left.parent = tree;
                        this.resizeTree();
                        if (needFix) {
                            this.cmd("SetText", 0, "Coloring child of deleted node black");
                            this.cmd("Step");
                            tmp.left.blackLevel++;
                            if (tmp.left.phantomLeaf) {
                                this.cmd("SetLayer", tmp.left.graphicID, 0);
                            }

                            this.fixNodeColor(tmp.left);
                            this.fixExtraBlack(tmp.left);
                            if (tmp.left.phantomLeaf) {
                                this.cmd("SetLayer", tmp.left.graphicID, 1);
                            }

                        } else {
                            this.cmd("SetText", 0, "删除的是红色节点.  不需要旋转.");
                            this.cmd("Step");
                        }
                    }
                }
                tmp = tmp.parent;

            }
        } else if (valueToDelete < tree.data) {
            if (tree.left != null) {
                this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
                this.cmd("Move", this.highlightID, tree.left.x, tree.left.y);
                this.cmd("Step");
                this.cmd("Delete", this.highlightID);
            }
            this.treeDelete(tree.left, valueToDelete);
        } else {
            if (tree.right != null) {
                this.cmd("CreateHighlightCircle", this.highlightID, HIGHLIGHT_COLOR, tree.x, tree.y);
                this.cmd("Move", this.highlightID, tree.right.x, tree.right.y);
                this.cmd("Step");
                this.cmd("Delete", this.highlightID);
            }
            this.treeDelete(tree.right, valueToDelete);
        }
    } else {
        this.cmd("SetText", 0, "元素 " + valueToDelete + " 未找到, 无法删除");
    }

}


RedBlack.prototype.fixNodeColor = function (tree) {
    if (tree.blackLevel == 0) {
        this.cmd("SetForegroundColor", tree.graphicID, FOREGROUND_RED);
        this.cmd("SetBackgroundColor", tree.graphicID, BACKGROUND_RED);
    } else {
        this.cmd("SetForegroundColor", tree.graphicID, FOREGROUND_BLACK);
        if (tree.blackLevel > 1) {
            this.cmd("SetBackgroundColor", tree.graphicID, BACKGROUND_DOUBLE_BLACK);
        } else {
            this.cmd("SetBackgroundColor", tree.graphicID, BACKGROUND_BLACK);
        }
    }
}


RedBlack.prototype.resizeTree = function () {
    var startingPoint = this.startingX;
    this.resizeWidths(this.treeRoot);
    if (this.treeRoot != null) {
        if (this.treeRoot.leftWidth > startingPoint) {
            startingPoint = this.treeRoot.leftWidth;
        } else if (this.treeRoot.rightWidth > startingPoint) {
            startingPoint = Math.max(this.treeRoot.leftWidth, 2 * startingPoint - this.treeRoot.rightWidth);
        }
        this.setNewPositions(this.treeRoot, startingPoint, startingY, 0);
        this.animateNewPositions(this.treeRoot);
        this.cmd("Step");
    }

}

RedBlack.prototype.setNewPositions = function (tree, xPosition, yPosition, side) {
    if (tree != null) {
        tree.y = yPosition;
        if (side == -1) {
            xPosition = xPosition - tree.rightWidth;
            tree.heightLabelX = xPosition - 20;
        } else if (side == 1) {
            xPosition = xPosition + tree.leftWidth;
            tree.heightLabelX = xPosition + 20;
        } else {
            tree.heightLabelX = xPosition - 20;
        }
        tree.x = xPosition;
        tree.heightLabelY = tree.y - 20;
        this.setNewPositions(tree.left, xPosition, yPosition + heightDelta, -1)
        this.setNewPositions(tree.right, xPosition, yPosition + heightDelta, 1)
    }

}
RedBlack.prototype.animateNewPositions = function (tree) {
    if (tree != null) {
        this.cmd("Move", tree.graphicID, tree.x, tree.y);
        this.animateNewPositions(tree.left);
        this.animateNewPositions(tree.right);
    }
}

RedBlack.prototype.resizeWidths = function (tree) {
    if (tree == null) {
        return 0;
    }
    tree.leftWidth = Math.max(this.resizeWidths(tree.left), widthDelta / 2);
    tree.rightWidth = Math.max(this.resizeWidths(tree.right), widthDelta / 2);
    return tree.leftWidth + tree.rightWidth;
}


RedBlack.prototype.disableUI = function (event) {
    this.insertField.disabled = true;
    this.insertButton.disabled = true;
    this.deleteField.disabled = true;
    this.deleteButton.disabled = true;
    this.findField.disabled = true;
    this.findButton.disabled = true;
    this.printButton.disabled = true;
}

RedBlack.prototype.enableUI = function (event) {
    this.insertField.disabled = false;
    this.insertButton.disabled = false;
    this.deleteField.disabled = false;
    this.deleteButton.disabled = false;
    this.findField.disabled = false;
    this.findButton.disabled = false;
    this.printButton.disabled = false;
}


/////////////////////////////////////////////////////////
// Red black node
////////////////////////////////////////////////////////


function RedBlackNode(val, id, initialX, initialY) {
    this.data = val;
    this.x = initialX;
    this.y = initialY;
    this.blackLevel = 0;
    this.phantomLeaf = false;
    this.graphicID = id;
    this.left = null;
    this.right = null;
    this.parent = null;
    this.height = 0;
    this.leftWidth = 0;
    this.rightWidth = 0;
}

RedBlackNode.prototype.isLeftChild = function () {
    if (this.parent == null) {
        return true;
    }
    return this.parent.left == this;
}


/////////////////////////////////////////////////////////
// Setup stuff
////////////////////////////////////////////////////////


var currentAlg;

function init() {
    var animManag = initCanvas();
    currentAlg = new RedBlack(animManag, canvas.width, canvas.height);
}